The Contribution of Preterm Birth to Infant Mortality Rates in the United States

Objective This study was aimed to examine differences in infant mortality outcomes across maternal age subgroups less than 20 years in the United States with a specific focus on racial and ethnic disparities. Study Design Using National Center for Health Statistics cohort-linked live birth–infant death files (2009-2013) in this cross-sectional study, we calculated descriptive statistics by age (<15, 15–17, and 18–19 years) and racial/ethnic subgroups (non-Hispanic white [NHW], non-Hispanic black [NHB], and Hispanic) for infant, neonatal, and postneonatal mortality. Adjusted odds ratios (aOR) were calculated by race/ethnicity and age. Preterm birth and other maternal characteristics were included as covariates. Results Disparities were greatest for mothers <15 and NHB mothers. The risk of infant mortality among mothers <15 years compared to 18 to 19 years was higher regardless of race/ethnicity (NHW: aOR = 1.40, 95% confidence interval [CI]: 1.06–1.85; NHB: aOR = 1.28, 95% CI: 1.04–1.56; Hispanic: aOR = 1.36, 95%CI: 1.07–1.74). Compared to NHW mothers, NHB mothers had a consistently higher risk of infant mortality (15–17 years: aOR = 1.12, 95% CI: 1.03–1.21; 18–19 years: aOR = 1.21, 95% CI: 1.15–1.27), while Hispanic mothers had a consistently lower risk (15–17 years: aOR = 0.72, 95% CI: 0.66–0.78; 18–19 years: aOR = 0.74, 95% CI: 0.70–0.78). Adjusting for preterm birth had a greater influence than maternal characteristics on observed group differences in mortality. For neonatal and postneonatal mortality, patterns of disparities based on age and race/ethnicity differed from those of overall infant mortality. Conclusion Although infants born to younger mothers were at increased risk of mortality, variations by race/ethnicity and timing of death existed. When adjusted for preterm birth, differences in risk across age subgroups declined and, for some racial/ethnic groups, disappeared. Key Points

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The evolution of infant mortality inequality in the United States, 1960–2016

Science Advances ◽

10.1126/sciadv.aba5908 ◽

2020 ◽

Vol 6 (29) ◽

pp. eaba5908

Author(s):

Nick Turner ◽

Kaveh Danesh ◽

Kelsey Moran

Keyword(s):

United States ◽

Infant Mortality ◽

The United States ◽

Mortality Rates ◽

County Level ◽

Level Data ◽

Antipoverty Programs ◽

The Relationship ◽

Over Time ◽

Mortality Inequality

What is the relationship between infant mortality and poverty in the United States and how has it changed over time? We address this question by analyzing county-level data between 1960 and 2016. Our estimates suggest that level differences in mortality rates between the poorest and least poor counties decreased meaningfully between 1960 and 2000. Nearly three-quarters of the decrease occurred between 1960 and 1980, coincident with the introduction of antipoverty programs and improvements in medical care for infants. We estimate that declining inequality accounts for 18% of the national reduction in infant mortality between 1960 and 2000. However, we also find that level differences between the poorest and least poor counties remained constant between 2000 and 2016, suggesting an important role for policies that improve the health of infants in poor areas.

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Comparison of Neonatal and Infant Mortality Rates between Infants Born in South Korea and Those Born in the United States

Neonatal Medicine ◽

10.5385/nm.2014.21.4.211 ◽

2014 ◽

Vol 21 (4) ◽

pp. 211 ◽

Cited By ~ 2

Author(s):

Ji Sun Lee ◽

Jung Min Yoon ◽

Eun Jung Cheon ◽

Kyong Og Ko ◽

Jae Won Shim ◽

...

Keyword(s):

United States ◽

Infant Mortality ◽

South Korea ◽

The United States ◽

Mortality Rates

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Regional Contribution of Previable Infant Deaths to Infant Mortality Rates in the United States

American Journal of Perinatology ◽

10.1055/s-0039-1695014 ◽

2019 ◽

Author(s):

MacKenzie Lee ◽

Eric S. Hall ◽

Meredith Taylor ◽

Emily A. DeFranco

Keyword(s):

United States ◽

Infant Mortality ◽

Infant Death ◽

The United States ◽

Mortality Rates ◽

Population Based ◽

Infant Mortality Rate ◽

Infant Deaths ◽

Live Births ◽

Healthy People 2020

Objective Lack of standardization of infant mortality rate (IMR) calculation between regions in the United States makes comparisons potentially biased. This study aimed to quantify differences in the contribution of early previable live births (<20 weeks) to U.S. regional IMR. Study Design Population-based cohort study of all U.S. live births and infant deaths recorded between 2007 and 2014 using Centers for Disease Control and Prevention's (CDC's) WONDER database linked birth/infant death records (births from 17–47 weeks). Proportion of infant deaths attributable to births <20 vs. 20 to 47 weeks, and difference (ΔIMR) between reported and modified (births ≥20 weeks) IMRs were compared across four U.S. census regions (North, South, Midwest, and West). Results Percentages of infant deaths attributable to birth <20 weeks were 6.3, 6.3, 5.3, and 4.1% of total deaths for Northeast, Midwest, South, and West, respectively, p < 0.001. Contribution of < 20-week deaths to each region's IMR was 0.34, 0.42, 0.37, and 0.2 per 1,000 live births. Modified IMR yielded less regional variation with IMRs of 5.1, 6.2, 6.6, and 4.9 per 1,000 live births. Conclusion Live births at <20 weeks contribute significantly to IMR as all result in infant death. Standardization of gestational age cut-off results in more consistent IMRs among U.S. regions and would result in U.S. IMR rates exceeding the healthy people 2020 goal of 6.0 per 1,000 live births.

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Letter To The Editor

PEDIATRICS ◽

10.1542/peds.45.6.1044 ◽

1970 ◽

Vol 45 (6) ◽

pp. 1044-1044

Author(s):

Alfred Yankauer

Keyword(s):

United States ◽

Infant Mortality ◽

Infant Death ◽

The United States ◽

Mortality Rates ◽

European Countries ◽

Death Rates ◽

Letter To The Editor

Second, Dr. Yankauer: "Disgraceful and totally unacceptable" are inflammatory adjectives. They stir up uncomfortable feelings of personal guilt and blame. It would be reassuring if the differences between infant mortality rates in the United States and those of several small European countries with relatively homogenous populations and stable traditions could be explained away as statistical artefacts. Unfortunately the differences cannot be explained away. Clear evidence for their substance is the fact that infant death rates after the first month of life are three times as high in the United States as in Sweden.

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Infectious Disease-Related Deaths of Low Birth Weight Infants, United States, 1968 to 1982

PEDIATRICS ◽

10.1542/peds.84.2.296 ◽

1989 ◽

Vol 84 (2) ◽

pp. 296-303

Author(s):

Janine M. Jason

Keyword(s):

Infectious Disease ◽

United States ◽

Birth Weight ◽

Infant Mortality ◽

Low Birth Weight ◽

Infectious Diseases ◽

The United States ◽

Mortality Rates ◽

Mortality Data ◽

Tract Infections

Infant mortality rates in the United States are higher than in any other developed country. Low birth weight (LBW) is the primary determinant of infant mortality. Despite city, state, and federal programs to prevent LBW, decreases in infant mortality in the 1980s appear to be largely secondary to improved survival of LBW infants rather than to a decline in the rate of LBW births. Because prevention of mortality due to infectious disease is feasible, it was of interest to examine the role of infectious diseases in LBW infant mortality. US vital statistics mortality data for 1968 through 1982 were analyzed in terms of LBW infant mortality associated with infectious and noninfectious diseases. These analyses indicated that the rates of infectious disease-associated early neonatal and postneonatal LBW mortality increased during this time; late neonatal rates did not decline appreciably. Infectious diseases were associated with 4% of all LBW infant deaths in 1968; this had increased to 10% by 1982. Although LBW infant mortality rates associated with noninfectious diseases did not differ for white and black populations, infectious disease-associated mortality rates were consistently higher for blacks than whites in both metropolitan and nonmetropolitan areas. Chorioamnionitis was involved in 28% of infectious disease-associated early neonatal LBW deaths. Sepsis was an increasingly listed cause of death in all infant age periods, whereas respiratory tract infections were decreasingly listed. Necrotizing enterocolitis increased as a cause of late neonatal mortality. These data suggest that infectious diseases are an increasing cause of LBW infant mortality and these deaths occur more frequently in the black population targeted by prevention programs. More research concerning specific causes and prevention of infections in the LBW infant may help reduce US infant mortality.

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